Neurostimulation has been applied to modulate various physiologic functions and treat various diseases. One example is the modulation of cardiac functions using autonomic modulation therapy (AMT) such as vagus nerve stimulation (VNS) therapy in a patient suffering heart failure or myocardial infarction. The myocardium is innervated with sympathetic and parasympathetic nerves including the cardiac branches of the vagus nerve. Activities in the vagus nerve, including artificially applied electrical stimuli, modulate the heart rate and contractility (strength of the myocardial contractions). Electrical stimulation applied to the vagus nerve is known to decrease the heart rate and the contractility, lengthening the systolic phase of a cardiac cycle, and shortening the diastolic phase of the cardiac cycle. This ability of VNS is utilized, for example, to control myocardial remodeling.
Because a patient's physiological conditions and response to AMT changes over time, there is a need for providing adaptive control of the therapy.